1. Technical Field
The present invention relates generally to an improved data processing system, in particular to a method and apparatus for handling clock signals in a data processing system. Still more particularly, the present invention provides a method, apparatus, and computer instructions for managing system clock availability in a data processing system.
2. Description of Related Art
Processors in a data processing system rely on internal timing devices, such as clocks, to operate. In many data processing systems, the clock contains a quartz crystal which generates a constant flow of pulses to allow the processor to operate. Additionally, this clock, also referred to as a system clock, also provides a timing reference to all of the other hardware logic in a data processing system. Many improvements have been made in system availability. However, the system clock still remains as a single point of failure in a data processing system.
Many data processing systems include multiple clock units or cards. These systems are provisioned to use one clock as a default clock. The selection of the default clock is preset. As a result, when a data processing system is booted, that data processing system is configured to use the default clock as a source for clock signals. If the default clock is faulty or fails, then the data processing system must be set to use a secondary clock as a source of clock signals.
The present invention recognizes that in absence of processes or apparatus for managing clocks in a data processing system is present. Therefore, it would be advantageous to have an improved method, apparatus, and computer instructions for managing system clocks and increasing availability of functional clock sources in a data processing system.